1. Field of the Invention
The present invention relates to imaging devices, and in particular, the present invention relates to a small imaging device installed in an electronic apparatus.
2. Description of the Related Art
Nowadays, small imaging devices in which a photoelectric conversion element, such as a complementary metal oxide semiconductor (CMOS) sensor or a charge coupled device (CCD) sensor, is integrated with a lens are often installed in electronic apparatuses, such as cellular phones or information processing terminals. As electronic apparatuses become miniaturized, imaging devices must be further miniaturized. As a result, packaging of imaging devices including CMOS sensor chips or CCD sensor chips is an important matter.
For example, Japanese Patent No. 3207319 (corresponding to U.S. Pat. Nos. 5,506,401 and 5,786,589) discloses a packaged structure in which a photoelectric conversion element is connected to a wiring board with an anisotropic conductive film by face down bonding and an optical glass disposed on the wiring board so as to be opposite to the photoelectric conversion element. Attaching an imaging lens to a packaged sensor chip having such a packaged structure with a supporting unit realizes an imaging device including an integrated lens.
FIG. 22 shows a typical example of an imaging device including a packaged sensor chip disclosed in Japanese Patent No. 3207319 with an integrated lens. The imaging device includes a packaged sensor chip 120, a barrel 122, and a holding unit 123 for holding the barrel 122. The barrel 122 holds an imaging lens 121 by bonding and includes an opening 125 functioning as a diaphragm. The holding unit 123 is bonded to the packaged sensor chip 120.
The barrel 122 and the holding unit 123 are coupled with a threaded mechanism, so that changing the position of the barrel 122 along the optical axis with respect to the holding unit 123 can adjust the focus of the imaging lens 121 at a photoelectric conversion element 124 of the packaged sensor chip 120. After the focus is adjusted, the barrel 122 is bonded and fixed to the holding unit 123.
However, the imaging apparatus including an integrated lens shown in FIG. 22 has any one of the following disadvantages:    (1) In order to adjust the focus of the imaging lens 121, the barrel 122 and the holding unit 123 are necessary components, thus increasing the number of components and the number of manufacturing steps.    (2) Although the focus of the imaging lens 121 can be adjusted, the inclination of the imaging lens 121 cannot be adjusted. Therefore, image degradation resulting from the inclination of the imaging lens 121 is expected.    (3) If the imaging lens 121 is made of plastic, the imaging lens 121 is very susceptible to environmental changes such that it is very difficult to accurately hold the imaging lens 121. If the imaging lens 121 is a molded glass lens, the cost of manufacture increases.